| Winter Protection |
 Following a long summer of growth, your woody plants are now readying themselves for the harsh realities of winter. Early frosts, very cold temperatures, radiation cooling, and snow and ice are just around the corner. Each and every one of them can either cause significant plant damage or kill plants outright. Don’t let this happen to your plants. By following a few of the simple cultural care practices I’ve described below, you can keep them plants out of harm’s way. Implement these measures before the soil freezes, end of November in Rhode Island and Southern New England for best results.
1. Apply a layer of mulch around plants. Mulching provides many benefits for plants. An application of mulch over the roots of plants keeps the soil warm, much like a blanket on a bed. This “extra warmth” is just enough to prevent cold temperature injury to tender roots in early winter. Also, frozen soil locks up water normally available to plants. This can cause plants to wilt and eventually die as water loss ( evapo-transpiration ) far exceeds the ability of roots to absorb water. This is a common problem with fall planted evergreens. Water will stay fluid much longer under mulched soil than naked soil, helping to avoid this type of water deficit problem associated with late season plantings. See pictures 1, 2 of mulched trees. 
2. Protect young trees from lower trunk frost cracking. Frost cracking is a type of low temperature injury associated with young, thin barked trees. A rapid temperature drop, sunny afternoons followed by very cold night-time temperatures appears to be the main culprit. This huge temperature differential as high as 30 F causes wood and cambial tissues under the tender bark to lose moisture, contract, and then die. The classic visual symptom of this type of cold damage is the vertical splitting of the lower trunk bark. This condition is also referred to as “sun-scald” and is usually more pronounced on the southwest side of trees in the Northern Hemisphere. All young trees, less than 15 years old, maples, birch and beech with thin bark are most susceptible. Frost injury can easily be prevented by protecting the internal trunk tissues from “cooking” on sunny, winter days. Just apply a coat of white latex paint around the trunk up to about 4 feet from the ground. The white paint will reflect the radiant energy of the sun away from the trunk. The result is that the excessive heat build-up will not occur and plant tissues under the bark will be unharmed. Another method is to wrap the trunk with aluminum foil. This material is also highly reflective and just as effective as white paint in moderating daily temperature extremes. See pictures 3, 4. 
3. Prevent Snow and Ice Damage to Evergreens. Inspect your evergreens. Do they have good structural traits such as a strong central leader, well-tapered lateral stems and good branch spacing along the trunk? If they do, then your evergreens have what is called “good sheddability”; that is the ability to shed or reduce the build-up of snow and ice to dangerous levels. They are ready for winter’s onslaught and should come through it unscathed in spring. But if your evergreens lack these traits, watch out, they may be in for a long winter and possibly subject to damage along the way. So check them out. Look for those bad traits that act as the tight corners in trees. They include co-dominate stems, narrow crotches and clustered shoots on individual branches. They all form nice places for ice and snow to gather in large amounts. Unfortunately, when these amounts by weight exceed the mechanical strength of the branch something has to give. In most cases, it’s the over-loaded branch or smaller diameter stems. They either crack, break in half, or bend limply never to re-gain their former shape. These are all disfiguring injuries that, even in mild cases, can affect the long term health and appearance of the plant. So rid your evergreens of these potentially damaging problems. This can be accomplished by pruning out the offending branches. By eliminating these bad defects, you will improve the plant’s structure and, by design, the plant’s ability to distribute snow and ice more evenly throughout the crown. Evergreens need an edge in winter. The edge in this instance is plant sheddability. Improve it, and you will help to buffer your plants against harm this winter. Then, sit back and look forward to reaping the rewards next spring! |